Cord composed of filaments or strands of different diameters



Dec. 19, 1967 G. PE1-:NE 3,358,435 CORD COMPOSED 0F FILAMENTS 0R STRANDS OF DIFFERENT DIAMETERS ed Apr 965 il 16, l

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bySparrow and Sparrow ATTORNEYS.

Patented Dec. 19, 1967 3,358,435 CORD COMPGSED F FILAMENTS OR STRANDS OF DIFFERENT DIAMETERS Guido Peene, Zwevegem, Belgium, assignor to Trefiieries Leon Bekaert, SpRL, Zwevegem, Belgium Filed Apr. 16, 1965, Ser. No. 448,662 Claims priority, application Belgium, Nov. 12, 1964, 655,593 4 Claims. (Cl. 57-145) ABSTRACT OF THE DISCLOSURE A cord for reinforcing articles made of rubber or the like elastic and resilient materials, which has a greater tensile strength and a fatigue resistance for a comparative outside diameter.

This invention relates to cables or cords to be used for reinforcing elastic or resilient articles made of rubber, plastic or the like materials, and particularly to cords such as are used for reinforcing pneumatic tires, conveyor belts, power transmission belts, hoses for high pressure and the like articles.

It is known that for certain reinforcement purposes such as, for example, in breakers of heavy tires, more rigid and less expensive cables or cords are desirable. However, cables or cords of such kind have various disadvantages, particularly of considerable reduction of the numerical value of their fatigue resistance against flexing, compared with cables or cords ofthe conventional construction composed of wire filaments of a finer gauge, for example, as described in U.S. Letters Patent No. 3,032,963.

On the other hand, the highest possible amount of tensile strength per unit of section area is required, particularly for reinforcing conveyor belts, power transmission belts or the like. In such cases, however, certain limitations in dimensions for the diameter of the cord exist; furthermore, the proportions of rubber to steel determine the size of the reinforcing cords. A greater tensile strength per unit of cord surface can be obtained by using heavier wire filaments in the construction of the cord; however, this is achieved at the expense of the numerical value of the fatigue resistance.

This invention is directed to a solution of this problem and consists in such novel features, construction arrangements, combinations of parts and improvements as may be shown and described in connection with the article herein disclosed by way of example only as illustrative of a preferred embodiment. Objects and advantages of the invention will be set forth in part hereafter and in part will be obvious herefrom or may be learned by practicing the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

It is an object of the present invention toprovide cords composed of heavier gauge filaments, such as, for example, wire filaments for a comparative outside diameter of the finished cord.

Another object of the present invention is to provide cords having an improved and increased tensile strength together with an increased numerical value of fatigue resistance.

Yet another object ofl the present invention `is to provide cords having an improved inner wear resistance.

A further object of the present invention is to provide a cord having an improved surface contact between the outer elements composing the jacket and the core strands, and minimum of wear between the jacket elements and the core due to their relative shifting when in use for reinforcing purposes, thus providing a cord with a high value of fatigue resistance.

Another object of the present invention is to improve the quality of cable or cord resulting from novel selection, arrangement and twisting of filament wires and wire strands composing the same.

A still further object of the present invention is to provide cords having an improved economic coefficient, that is, the quotient of the price per meter of cord per kilogram of tensile strength.

Various further and more specific purposes, features and advantages will clearly appear from the detailed description given below taken in connection with the accompanying drawing which forms part of this specification and illustrates merely by way of example one embodiment of the device of the invention.

In the following description and in the claims, parts will be identified by specific names for convenience, but such names are intended to be as generic -in their application to similar parts as the art will permit. Like reference characters denote like parts in the figures of the drawing, in which:

FIG. 1 shows in cross-section a cord according to the invention, drawn in an enlarged scale;

FIG. 2 illustrates in cross-section a conventional cord having a jacket composed of six outer wires surrounding a core composed of three wires.

Referring now in more detail to the drawing illustrat` ing a preferred embodiment by which the invention may be realized, there is shown in FIG. l a cable or cord having the general numeral 10 which is composed of a stranded core having the general numeral 20 and an outer jacket theresurrounding, comprising three filaments or wires 11 of one diameter, and three filaments or wires ,12 of another diameter. The core 10 consists of three filaments or wires 21 which are stranded together in conventional manner. It is understood that one or more of the single-filament wires 11 and 12 of the outer jacket may be replaced with wire strands.

In FIG. l, wires 11 and 12 are shown as single wire filaments for convenience. For example, elements 11 may consist of a plurality of smaller wires stranded together and elements 12 may consist of monolilaments, or vice versa, it being understood, however, that any combination of monoiilaments and stranded elements may be used in the construction of the outer jacket.

Cord 10, in its preferred form, has the following speciiic properties and unobvious advantages and features resulting from the novel selection and arrangement of its parts and elements and its construction therewith.

Gore 20 consists of three wires 12 of equal diameter d', which are stranded together with a pitch L and with a lay direction K. The theoretical diameter of core 20 is, as is known in the art, equal to 2.15d'. Three monofiiament wires 11, having a diameter D', equal to approximately 1.85d, are stranded together with core 20, h-aving the same pitch and the same lay direction as the wires of core 20, in such manner that they adjust with said core tangentially touching simultaneously the periphery of two of the wires of the core. The diameter D of the wire is selected according to the nature of the construction and with respect to the elliptic shape of the same, caused by the pitch. This shown in FIG. 1, which also illustrates how the other three monofilament wires 12 having a smaller diameter D2 equal to approximately 1.50d are stranded into the interstices between wires 11. The diameter D2 again is selected according to the nature of the construction and takes the final elliptic shape of the wires into account. Pitch and lay direction of the wires 12 again are the same as those 0f core 20 and wires 11. The resulting cable or cord is fully closed in the manner shown by the outer circle surrounding all elements in FIG. 1.

Typical examples of such cords are: for a heavier type of cord: 'c for the core: three wires each having a diameter of 0.23 mm. y for the jacket: three wires each having a diameter of 5 0.43 mm. and three wires each having a diameter of 0.345 mm. for a lighter type of cord:

for the core: three wires each having a diameter of 0.17 mm. for the jacket: three wires each having a diameter of 0.32 mm, and three wires each having a diameter of 0.26 mm.

The evaluation of this kind of construction indic-ates substantial advantages and features.

Each monofilament wire 12 may be substituted by a plurality of smaller wires stranded together, the outer diameter of which plurality of twisted wires is D. Similarly, each monofilament wire 11 maybe substituted by a plurality of smaller wires stranded together, the cuter ldiameter of which plurality of twisted wires is D'2.

A substantial increase of the numerical value of the fatigue resistance results from the linear contact between the elements of the outer jacket and the filaments of the stranded core because of both the equal pitch and lay direction of these elements and filaments. Obviously the contact area between the elements and filaments is much larger and the inevitable wear due to the movement of these parts relative to one another is less. In the same sense, the closer fitting of wires of jacket and strand of core reduces the friction between these parts and slows down or reduces Vthe wear.

Normally, the uni-directional or concurrent lay of a cable results in a numerical value of fatigue resistance which is higher than in case of -a cross-lay; however, a cable or cord made according to the present invention, having the same diameter as a conventionally-constructed cable or cord, such as is shown in FIG. 2, a numerical value of fatigue is obtained which is up to 40% higher.

Furthermore, an increase of tensile strength is obtained 40 by the cable construction according to the present invention. By comparing this cable with a conventional cable, such as that depicted in FIG. 2, having the same outside diameter, and reducing all dimensions to the diameter d of wires 41 of core strand 40 of said conventional cable, the following equations result:

In a conventional cord or cable: outside cable diameter:

In cable or cord according to the present invention:

Wherefrom the following comparison is obtained:

Cord or cable according to the present invention Conventional cord or cable total surface Thus, the degree of filling or total -used surface of the cord or cable, according to the present invention, is 8.35% higher than that yof a conventional cord or cable having the same outside diameter and having the same number of stranded wires. Since the sum total of the wire sections in the cord or cable of the present invention is so much higher, it is obvious that the tensile strength of the cord or cable also is increased by this amount, all specific values such as tensile strength of the material of the wires and loss of cabling being equal. i

A further important result is obtained by the facility of increasing the diameter of the filaments or monoilarnents in the construction of the cable or cord according to this invention by 4-5%, in that the price of the cord or cable decreases since the cost of manufacturing the strands and the cabling remain the same. The conventional index figure of the quality of a cable, called the Economic Coefficient, is the relation between the cost or price per meter of cable and the kilograms of tensile strength. It is clearly evident that the Economic Coefficient of the cables or cords made according to the present invention is significantly improved.

Obviously, cabled cord can be further combined with other elements, for example, by spirally winding additional wires, strands or like elements around the outer jacket of the cord or cable, or by cabling together several cords made according to the present invention for obtaining heavier cables, or the like combinations. It is also understood that the monofilaments of which the strands of the core and of which the outer'jacket consists, can be plated with non-ferrous metals such as copper, nickel, beryllium, titanium, brass, tin, zinc or the like non-ferrous metals, or may be coated with anti-corrosive coatings of organic and inorganic character, such as, for example, paint, latex, polystyrene, polytetrailuoroethylene, polyvinyl, nylon, rayon, ceramics, etc., respectively, as circumstances may require it. In other words, cord or cable according to the present invention embodies all practical combinations of metallic and non-metalic coatings, as well as all practical elements disposed over the jacket of the cord or cable.

Furthermore, the elements of the outer jacket may be composed of monofilainents or strands or a combination of both, for example, alternately strands and monolaments and respective elements may have different characters, and may have different lay directions or pitches.

It is further understood that some of the filaments or monolaments or strands comprising the outer jacket and core may be made of plastic or other suitable nonmetallic material.

While the invention has been described and illustrated with respect to a certain preferred example which gives satisfactory results, it will be understood by those skilled in the art after understanding the principle of the invention, that various other changes and modifications may be made without departing from the spirit and scope of the invention and it is intended therefore in the appended claims to cover all such changes and modifications.

I claim:

1. Cord for reinforcing articles made of rubber, plastic or the like materials, comprising a center core composed of three monofilaments having the same diameters, said mono'ilaments twisted to a strand, and an outer jacket surrounding said cord, said jacket being composed of six elements, first three of said elements having the equal diameters fitting respectively tangentially in contacting engagement with two adjacent monotlaments of said core, said first three elements having a diameter of substantially 1.85 times the diameter of one of said monofilaments of said core, and the remaining three of said elements having equal diameters but differing in diameter size from the first three elements, said three remaining elements having a diameter of substantially 1.5 times the diameter of one of said monoiilaments of said core and fitting respectively in the spaces between said first three elements, said six elements being twisted around said core.

2. Cord for reinforcing articles made of rubber, plastic 0r the like materials, comprising a center core composed 0f three wires having the same diameters, said wires twisted to a strand with both a predetermined pitch and lay, and a jacket surrounding said core, said jacket being composed of six elements, the rst three of said elements having equal diameters iitting respectively tangentially in contacting engagement with two adjacent wires of said core, said rst three elements having a diameter of substantially 1.85 times the diameter of one of said wires of said core, and the remaining three of said elements having equal diameters but differing in diameter size from the first three elements, said three remaining elements having a diameter of substantially 1.5 times the diameter of one of said Wires of said core and fitting respectively in the spaces between said first three elements, said six elements vbeing twisted around said core with both the same predetermined pitch and lay as said core.

3. Cord according to claim 1, said six elements of said jacket consisting of monofilament wires.

4. Cord according to claim 2, said six elements of said jacket consisting of strands composed of a plurality of monofilament wires.

References Cited UNITED STATES PATENTS 2,348,234 5/1944 Warren 57-147 2,863,279 12/1958 Dietz 57-147 FRANK I. COHEN, Primary Examiner. D. E. WATKINS, Assistant Examiner. 

1. CORD FOR REINFORCING ARTICLES MADE OF RUBBER, PLASTIC OR THE LIKE MATERIALS, COMPRISING A CENTER CORE COMPOSED OF THREE MONOFILAMENTS HAVING THE SAME DIAMETERS, SAID MONOFILAMENTS TWISTED TO A STRAND, AND AN OUTER JACKET SURROUNDING SAID CORD, SAID JACKET BEING COMPOSED OF SIX ELEMENTS, FIRST THREE OF SAID ELEMENTS HAVING THE EQUAL DIAMETERS FITTING RESPECTIVELY TANGENTIALLY IN CONTACTING ENGAGEMENT WITH TWO ADJACENT MONOFILAMENTS OF SAID CORE, SAID FIRST THREE ELEMENTS HAVING A DIAMETER OF SUBSTANTIALLY 1.85 TIMES THE DIAMETER OF ONE OF SAID MONOFILAMENTS OF SAID CORE, AND THE REMAINING THREE OF SAID ELEMENTS HAVING EQUAL DIAMETERS BUT DIFFERING IN DIAMETER SIZE FROM THE FIRST THREE ELEMENTS, SAID THREE REMAINING ELEMENTS HAVING A DIAMETER OF SUBSTANTIALLY 1.5 TIMES THE DIAMETER OF ONE OF SAID MONOFILAMENTS OF SAID CORE AND FITTING RESPECTIVELY IN THE SPACES BETWEEN SAID FIRST THREE ELEMENTS, SAID SIX ELEMENTS BEING TWISTED AROUND SAID CORES. 